Biochemical and Biophysical Research Communications, Vol.517, No.3, 477-483, 2019
Activation of CaMKK beta-AMPK-mTOR pathway is required for autophagy induction by beta,beta-dimethylacrylshikonin against lung adenocarcinoma cells
beta,beta-Dimethylacrylshikonin (DMAS), an active ingredient of Lithospermum erythrorhizon and Arnebia euchroma, possess anti-neoplasm properties. Recently, DMAS was reported to stimulate autophagy in lung adenocarcinoma cells. However, the mechanisms by which DMAS modulates autophagy. have not yet been clearly elucidated. In this study, we found that DMAS significantly elevated intracellular free calcium accumulation. This activated the CaMKK beta-AMPK-mTOR pathway, subsequently inhibited mTOR and its substrate p70s6k and 4E-BP1, eventually leading to autophagy. In addition, we demonstrated that inhibition of autophagy by BAPTA-AM or STO-609 or compound C potently enhanced DMAS-induced lung adenocarcinoma cells apoptosis and growth inhibition. Overall, our results suggested that cytoprotective autophagy was triggered by DMAS via CaMKK beta-AMPK-mTOR signaling cascade in human lung adenocarcinoma cells, meaning that combining use of DMAS and autophagy inhibitors as a novel therapeutic option for lung adenocarcinoma will be very promising. (C) 2019 Elsevier Inc. All rights reserved.